The present invention relates to video encoding and video decoding, and more particularly, to video encoding method and apparatus with syntax element signaling of an employed projection layout and associated video decoding method and apparatus.
Virtual reality (VR) with head-mounted displays (HMDs) is associated with a variety of applications. The ability to show wide field of view content to a user can be used to provide immersive visual experiences. A real-world environment has to be captured in all directions resulting in an omnidirectional video corresponding to a viewing sphere. With advances in camera rigs and HMDs, the delivery of VR content may soon become the bottleneck due to the high bitrate required for representing such a 360-degree image content. When the resolution of the omnidirectional video is 4K or higher, data compression/encoding is critical to bitrate reduction.
In general, the omnidirectional video corresponding to a viewing sphere is transformed into a frame with a 360-degree image content represented by projection faces arranged in a 360-degree Virtual Reality (360 VR) projection layout, and then the resulting frame is encoded into a bitstream for transmission. If a configuration of the employed 360 VR projection layout is fixed without allowing any adjustments made thereto, the video encoder has less flexibility for encoding the 360-degree image content. Thus, there is a need for a flexible video encoder design which is allowed to determine/select a 360 VR projection layout and signal syntax element(s) associated with the employed 360 VR projection layout to a video decoder.